There is known a technique for dividing calculation resources, such as a memory, a CPU time, and so forth, of a computer so that a plurality of programs are executed using the respective calculation resources. According to this technique, a general purpose program, such as a system setting program and so forth, is installed beforehand in a computer so that the program can be executed at any time, when execution thereof is required while an application program installed after the installation of the general purpose program is being executed. This arrangement improves user convenience, and as duplicated development of a general purpose program can be avoided, also improves development efficiency.